626 SELECTIONS FROM ADDRESSES. 



ments of the crop mnst be contained in the soil in abundance; 

 2d, they must be in such a state as to form the proper com- 

 pounds ; 3d, there mus^ be no deleterious matters existing in 

 the soil. When these conditions are fulfilled, maximum crops 

 may be obtained. 



The quantity of organic matter in soils varies from one-half 

 to 70 per cent, of their whole weight. Corn cannot grow with 

 so small a proportion as the former, nor would its cultivation 

 be profitable when it is as great as the latter. Good corn 

 soils contain about five per cent, of organic matter, and the 

 very best rarely contain more than ten per cent. The re- 

 mainder of the soil consists of pulverized rocks, formed either 

 from the layers beneath them or brought from a distance by 

 the agency of aqueous currents. 



An analysis of the soil will show its actual condition, and 

 will enable the farmer to add what is lacking and neutralize 

 what is deleterious. 



It may be useful to mention the amount required of hog 

 manure or cow manure, to supply the materials of a crop 

 of corn, such as we have been describing. To supply the 

 silicic acid 12,400 lbs. of hog manure, or 13,200 lbs. of cow 

 manure, would be required. For the sulphuric acid, 20,000 

 lbs. of hog manure, or 15,800 lbs. cow manure. For the 

 phosphoric acid, 8,860 lbs. hog manure, or 22,900 lbs. of cow 

 manure. For the lime, 16,000 lbs. of hog or cow manure. 

 For the magnesia, 23.700 lbs. hog manure, or 18,600 lbs. of 

 cow manure. For the potash, 54,100 lbs. hog manure, or 

 25,000 lbs. cow manure. For the soda, 16,100 lbs. of hog 

 manure, or 10,600 lbs. cov7 manure. P'or the chlorine, 180,900 

 lbs. of hog manure, and ten times as much of cow manure. 

 Clijorophyl and wax, 40,700 lbs. of hog manure, or 42,700 lbs. 

 cow manure. For the fibre, 91,000 lbs. hog manure, or 95,000 

 lbs. cow manure. For the dextrine or gum, 66,200 lbs. hog, 

 or 68,600 lbs. cow manure. For the sugar and extract, 

 375,000 lbs. of hog or cow manure. For the albumen, 30,800 

 lbs. of hog, or 19,300 lbs. of cow manure. And for the caseine, 

 19,000 lbs. of hog, o.- 28,200 lbs. of cow manure. 



We have already explained that a part of the sugar, starch, 

 and fibre are obtained directly from the atmosphere, while the 

 remainder is drawn in through the roots. Since this portion 



